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nodding arnica, Parry's arnica

Rydberg's arnica, subalpine arnica, subalpine leopardbane

Habit Plants 15–50(–60) cm. Plants 8–35 cm.
Stems

simple or branched among heads.

(branches from rhizomes) simple.

Leaves

(2–)3–4 pairs, basal and cauline (basal usually withered by flowering, petiolate or subsessile, blades ovate or nearly round to oblong-ovate, much smaller than cauline; sterile rosettes often present, proximal cauline often crowded toward stems bases);

petiolate;

blades broadly to narrowly lanceolate, oblong-ovate, ovate-lanceolate, or round, 4–22 × 1–6 cm, (bases obtuse or cuneate to truncate) margins usually entire, sometimes sparsely denticulate, faces scantily to moderately pilose (hairs white), adaxial sparsely stipitate-glandular (distal cauline leaves sessile, extremely reduced, nearly linear to narrowly elliptic-lanceolate).

2–4 pairs (basal often persistent on sterile rosettes), mostly cauline;

petiolate (at least basal) or sessile;

blades oblanceolate to spatulate, 2–7 × 0.5–2.5 cm, margins usually entire, sometimes denticulate, rarely dentate, apices usually acute, sometimes obtuse, faces sparsely puberulent, moderately pubescent distally, stipitate-glandular.

Involucres

turbinate to narrowly campanulate.

turbinate-campanulate.

Ray florets

usually 0 (sometimes peripheral florets pistillate; corollas yellow, laminae rudimentary).

6–10;

corollas yellow.

Disc florets

20–50;

corollas yellow (1 or more lobes sometimes expanded, giving appearance of laminae);

anthers yellow.

corollas yellow;

anthers yellow.

Phyllaries

8–20, linear to narrowly lanceolate.

9–15, linear-oblong to narrowly lanceolate.

Heads

(1–)3–9(–14; often nodding in bud).

1–3(–5).

Cypselae

brown to black, 4–7 mm, glabrous or sparsely stipitate-glandular to densely hirsute;

pappi usually stramineous, rarely tawny, bristles barbellate to ± subplumose.

brown, 4–7 mm, densely hirsute (not stipitate-glandular);

pappi white, bristles barbellate.

2n

= 38, 57, 76.

= 38, 76.

Arnica parryi

Arnica rydbergii

Phenology Flowering May–Sep. Flowering Jul–Aug.
Habitat Open conifer forests to alpine meadows Dry to mesic, exposed, rocky alpine slopes and ridges or alpine meadows
Elevation 500–3800 m [1600–12500 ft] 1200–3400 m [3900–11200 ft]
Distribution
from FNA
CA; CO; ID; MT; NV; OR; UT; WA; WY; AB; BC; YT
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; ID; MT; OR; UT; WA; WY; AB; BC
[WildflowerSearch map]
[BONAP county map]
Source FNA vol. 21, p. 373. FNA vol. 21, p. 371.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Chaenactidinae > Arnica Asteraceae > tribe Heliantheae > subtribe Chaenactidinae > Arnica
Sibling taxa
A. acaulis, A. angustifolia, A. cernua, A. chamissonis, A. cordifolia, A. dealbata, A. discoidea, A. fulgens, A. gracilis, A. griscomii, A. lanceolata, A. latifolia, A. lessingii, A. lonchophylla, A. longifolia, A. louiseana, A. mollis, A. nevadensis, A. ovata, A. rydbergii, A. sororia, A. spathulata, A. unalaschcensis, A. venosa, A. viscosa
A. acaulis, A. angustifolia, A. cernua, A. chamissonis, A. cordifolia, A. dealbata, A. discoidea, A. fulgens, A. gracilis, A. griscomii, A. lanceolata, A. latifolia, A. lessingii, A. lonchophylla, A. longifolia, A. louiseana, A. mollis, A. nevadensis, A. ovata, A. parryi, A. sororia, A. spathulata, A. unalaschcensis, A. venosa, A. viscosa
Synonyms A. angustifolia subsp. eradiata, A. parryi subsp. sonnei, A. parryi var. sonnei
Name authority A. Gray: Amer. Naturalist 8: 213. (1874) Greene: Pittonia 4: 36. (1899)
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